There are a lot of aspects to it, but you have to consider the fact that Soccer isn't making people money like the other big sports in the US. There are likely costs that would prohibit underprivileged kids from participating in any of these sports, but other people are probably willing to foot the bill if they think they can scout a young Lebron or whatever, it's an investment that those sports organizations can probably afford. The reverse if true for Europe etc. where you see these stories with the likes of Mbappe/Lukaku etc, the sport doesn't have that pull here.